AquaMatic makes two different 2-inch V42 diaphragm valves, and they take different parts. The V42F uses the 425 body. The V42G uses the 426 body, which is the larger of the two and the same casting used on the 2.5-inch V42H.
Side by side the difference in size is easy to see. The trouble is that you almost never have both valves in front of you. With one valve on the bench and nothing to compare it against, three quarters of an inch is probably isn’t something easy to judge. Both valves are cast iron, both are Y-pattern, both are 2-inch NPT, and both carry the same casting marks.
If the tag is gone or unreadable, one way to distinguish is by measuring them.
A V42F measures 6.63 inches end to end. A V42G measures 7.35 inches.
That is the valve body casting only, measured across the full length from one port face to the other. Do not include unions, nipples, adapters, or anything threaded into the ports.
The difference is 0.72 inches, easy to see with a tape. Use this rule:
Measurement | Valve |
Under 6.9″ | V42F, 425 body |
Over 7.1″ | V42G, 426 body |
The 426 body serves both the 2-inch V42G and the 2.5-inch V42H, so a measurement over 7.1 inches tells you that you have a 426 body but not yet which valve.
Pipe size settles it. A 2-inch port is a V42G. A 2.5-inch port is a V42H.
The V42G and the V42H share repair kits. Both take the 426-series diaphragm and seal kit and the 426-series internal parts kits. If you have been ordering different kits for your 2-inch and 2.5-inch valves, check that.
The V42F does not share with anything. The 425 body is used on that valve alone.
Once you know the body, the kit is determined by the body series, not by the pipe size.
| V42F | V42G and V42H |
Body series | 425 | 426 |
Diaphragm and seal kit, Buna N | 425-RA | 426-RA |
Internal parts, normally open | 425-RF | 426-RF |
Internal parts, normally closed | 425-RG | 426-RG |
EPDM and FKM variants exist for both series. The suffix pattern is consistent: RA is the base Buna N diaphragm and seal kit, RAE substitutes EPDM seals, RAV substitutes FKM.
A valve labelled V42G takes kits labelled 426. Nothing on the valve tells you that, and it is the most common reason the wrong kit gets ordered in this size range.
Both bodies come in several configurations, and each has its own part number. Normally open is the standard. Normally closed, limit stop, position indicator, spring assist open, and spring assist closed are separate builds rather than options bolted on afterwards.
Two things worth knowing before ordering a conversion:
The restrictions differ between the two bodies. Assuming they match is another way to end up with a part that will not fit.
Also watch the difference between repair kits and conversion kits. A limit stop repair kit services a valve that already has one. A limit stop conversion kit adds one to a valve that does not. The part numbers differ by a single letter and they are not interchangeable.
The WA125 marking. Many AquaMatic valves carry WA125 cast into the body. It describes the valve’s service rating, not its model, and both the F and the G can carry it. See what WA125 actually means.
Pipe size on its own. Both the F and the G are 2 inch. Size only helps once you have narrowed to the 426 body and need to separate the G from the H.
Appearance. Same material, same Y-pattern casting, same connection type. There is no bolt count or cap profile that separates them reliably.
Normally open versus normally closed. That is a configuration, and it applies to both bodies. It changes which internal parts kit you need, not which body you have. See normally open or normally closed.
If the tag on your AquaMatic V42 is missing, painted over, or corroded, answer two questions and we will tell you the model, the body series, and which repair kits fit it. Worth knowing up front: kits are named by body series, not by the model letter stamped on the valve.
QUESTION 1
YOUR VALVE
Kits that fit this valve
Send us a photo of the valve, with a tape measure in frame if you can, and we will confirm the model before you order. A wrong kit costs a return and a second shipment. A phone call costs two minutes.
Have the full part number instead? The valve identifier decodes it and confirms material, configuration, and seal materials in one step.
LET US TAKE A LOOK
Guessing here costs a return and a second shipment, so it is worth thirty seconds of ours. Photograph the valve with a tape measure in frame if you can, and include any markings cast into the body.
Or use the contact form if you would rather write it out.
If you have a full part number, our valve identifier decodes it and confirms model, size, material, configuration, and seal materials in one step.
Still not sure? Call 980.458.2583 or email sales@buyaq-matic.com with a photo. Include a tape measure in the shot if you can.
